Vibration damper

ABSTRACT

Damper of vibrations between two elements comprising a center rod adapted to be connected to one of the elements and a mount surrounding the rod and adapted to be connected to the other element. The rod and mount are interconnected by two elastically yieldable bell-shaped membranes. The latter have at their apices apertures in which the rod is engaged and are connected to the mount at their peripheries.

United States Patent 1 3,690,640 Pineau [45] Sept. 12, 1972 [54]VIBRATION DAMPER FOREIGN PATENTS OR APPLICATIONS [72] Inventor: AndreLucien Pineau, 12 Rue de 627,726 l/l963 Belgium ..267/l40 Beam 92,Saint-Cloud, France [22] Filed: Jan. 26, 1971 [2]] Appl. No.: 109,895

[30] Foreign Application Priority Data Feb. 3, 1970 France ..7003678{52] US. Cl. ..267/l37 [51] Int. Cl ..Fl6k 1/36 [58] Field of Search..267/l36, 137, 140, 141

[56] References Cited I UNITED STATES PATENTS 2,677,851 5/1954 Beyer..267/ 141 Primary Examiner-James B. Marbert Attorney-Marks & Clerk andJohn Lezdey [S 7] ABSTRACT Damper of vibrations between two elementscomprising a center rod adapted to be connected to one of the elementsand a mount surrounding the rod and adapted to be connected to the otherelement. The rod and mount are interconnected by two elasticallyyieldable bell-shaped membranes. The latter have at their apicesapertures in which the rod is engaged and are connected to the mount attheir peripheries.

11 Claims, 4 Drawing Figures The present invention relates to vibrationdampers between two members or structures.

Devices adapted to damp or absorb vibrations are known which comprisemainly a block of an elastomer material, for example rubber, mounted ona tubular spacer member adapted to be rendered integral with a firststructure, the block being provided in its median part with aperipheralrecess in which is engaged a ring adapted to be fixed to asecond structure.

The vibrations between the two structures are damped by the elasticdeformation of the block and by the internal hysteresis of the rubberemployed.

A damper of this type has a number of drawbacks:

Its frequency of resonanceis relatively high so that it can only afforda correct damping or absorption of vibrations in the neighborhood of 50Hz. g j

Further, as the block of elastomer material is held in the center partby the spacer tube, the radial deformation of the block is very limitedso that the damper is rendered less flexible. Moreover, thedampingcapacity of the known device depends practically solely on theelastically yieldable material employed in the block of the damper.Consequently, adamper of this type can only be employed for a verylimited range of loads for a given size.

An object of the invention is to remedy the aforementioned drawbacks andprovide a vibration damper which affords an effective damping offrequencies ranging from very low frequencies and which, while beingsimple in construction, is capable of operating under a wide range ofloads. v

The invention provides a damper of vibrations between two elements, suchas structures or members, comprising a center rod adapted to be renderedintegral with a first of the elements and a mount surrounding the rodand adapted to be rendered integral with the second element, wherein therod and the mount are interconnected by two elastically yieldablebell-shaped membranes, said membranes having apertures at their apicesin which said rod is engaged and peripheries which are connected to themount.

Further features and advantages of the invention will be apparent fromthe ensuing description with reference to the accompanying drawing.

In the drawing:

FIG. 1 is a sectional view of a first embodiment of the damper accordingto the invention;

FIG. 2 is a sectional view of a first modification of the damper shownin FIG. 1;

FIG. 3 is a sectional view of a second modification of the damper shownin FIG. I, and

FIG. 4 is a diagram showing a comparison of the performances of a damperof known type and those of a damper according to the invention.

The damper shown in FIG. 1 comprises a tube 1 provided at its ends withflanges 2 and adapted to be rendered integral with a first structure(not shown). The tube can be internally smooth or screwthreaded,depending on the manner in which it is fixed to the structure. A mount3, constituted by a metal plate 4 having a circular aperture 5, isclamped between two side walls 6 by rivets 8 or the like. Each wall 6has an annular curved portion 7 extended by a horizontal flange portion19. The mount 3 is connected to the tube 2 l by two elasticallyyieldable bell-shaped membranes 9 and 10. This mount can be renderedintegral with a second structure (not shown).

The apex of each membrane has an aperture containing the tube 1 and isretained by a flange 2 of the tube 1 which therefore acts as a spacermember.

The peripheries of the membranes 9 and l0bear in recesses defined by theportions 7 of the side walls 6 v beyond which the periphery of themembrane tends to I be pulled out of the recess.

The apices ofthe membranes 9, 10 are either slidably mounted on the tube1 and retained externally by flanges 2 or fixed to the flanges 2 byadhesion or vulcanization.

In the latter case, in the course of operation of the damper, if one ofthe membranes works under compression the other works under tension.

Themembranes 9 and 10 are provided in the known manner with smallorifices 11 whereby the interior of the damper is put in communicationwith the atmosphere so that there is no pneumatic effect on itsoperation.

The modificationof the damper according to the invention shownin FIG. 2comprises a spacer tube in two parts .la and lb. Thepart 1b of the tubehasone end 12 which is screwthreaded and on which is screwthreadedlyengaged the part lb so that the distance between the flanges 2a and 2bcan be adjusted and the membranes 9a and can be prestressed inaccordancewith requirements. A lock-nut l3 locks the part 1b on the partla. The membranes 9a and 10a also comprise sleeves 15 and 16 which arein one piece with the membranes and stiffen the latter locally.

FIG. 3shows a second modification of the damper according to theinvention, the mount 30 comprising the curved portion 7c and the flangesbeing made in one piece, for example by machining on a lathe. The tube10 of this damper has two shoulders 17, 18 adapted to cause the apicesof the membranes 9c, 10c to move with the spacer tube.

The membranes 9c and 100 have, moreover, a shape slightly different fromthose of the membranes in the dampers shown in the FIGS. 1 and 2.

It will be understood that the two modifications shown in FIGS. 2 and 3can be so combined as to provide a damper whose membranes are made tomove with the spacer tube and which can be prestressed in such manner asto adapt the response of the damper.

It is also possible to combine the possibilities of adhesion or abutmentof each of the membranes to suit the desired result, from example byleaving one membrane free and putting the other in abutting or adheredrelation so as to adapt the assembly to a preferential axis ofoperation.

In the dampers just described, the two membranes are identical. However,it is possible, according to needs, to dispose on each side of the mountmembranes having different thicknesses or mixtures which renders thedamper stiffer in respect of forces applied to the thicker or thestronger membrane.

FIG. 1 shows a diagram in which the curves in dotted line and in fullline respectively represent the transmissibility as a function of thefrequency of a damper of the known type mentioned hereinbefore and of adamper according to the invention.

It will be seen from these curves that the conventional damper has afrequency of resonance of 20 Hz. The damping zone only starts in theregion of 30 Hz and there still remains more than lpercent of vibratoryamplitude at 50 Hz. The amplitude thereafter decreases, but it stillretains an appreciable value beyond 70 Hz.

The damper according to the invention, when tested under the sameconditions of loads and vibratory amplitude, has a frequency ofresonance of less than Hz. The damping zone starts at 14 Hz. At 30 Hzthere remains only Spercent of the initial amplitude which thereafterdecreases regularly and eventually becomes negligible at about 50 Hz.

The damper according to the invention therefore has a much higherefficiency than that of the conventional damper in a zone correspondingto the frequencies between 15 and 50 Hz which are those most frequentlymet with in industrial applications.

Further, the possibility of prestressing the membranes according toneeds renders the damper of utility with a wider range of loads.Further, the fact that it is possible to connect the spacer tube to oneof the membranes or to both of them either by adhesion or vulcanizationof the apices of each membrane to the flanges of the spacer tube or byforming shoulders on the later in such manner as to wedge the apices ofthe membranes between the flanges and the shoulders, the damper can beadapted to the amplitude and to the direction of the loads to which itis subjected by the two structures between which it is mounted.

Having now described my invention what I claim and desire to secure byLetters Patent is:

l. A damper of vibrations between two elements, comprising a center rodadapted to be rendered integral with one of said elements, a mountsurrounding the rod and adapted to be rendered integral with the otherelement, two elastically yieldable bell-shaped membranes interconnectingsaid rod and said mount each membrane having an apex at which meansdefine an aperture in which said rod is engaged and a peripheryconnected to the mount.

2. A damper as claimed in claim 1, wherein said rod comprises at itsends flanges adapted to retain said apices of said membranes externally.

3. A damper as claimed in claim 2, wherein said apices of said membranesare fixed to said flanges by adhesion.

4. A damper as claimed in claim 2, wherein said apices of said membranesare fixed to said flanges by vulcanization.

5. A damper as claimed in claim 1, wherein said rod comprises two partsscrewed one into the other so as to make it possible to apply aprestressing to said membranes.

6. A damper as claimed in claim 1, wherein said rod further comprisesshoulders adapted to connect said apices of said membranes to said rodso that said membr nes move with sai r od.

A damper as calmed in claim 1, wherein said mount comprises two annularrecesses in which said peripheries of said membranes are held inposition.

8. A damper as claimed in claim 7, wherein the mount comprises a centerplate having an aperture through which said rod extends, two side wallsin clamped relation to said plate and having curved inner portions, saidannular recesses being defined by opposed faces of said plate and saidcurved portions of said side walls.

9. A damper as claimed in claim 8, wherein said membranes bear on saidopposed faces of said plate and on said curved portions of said sidewalls.

10. A damper as claimed in claim 7, wherein said mount is in a singlepiece.

11. A damper as claimed in claim 7, wherein said curved portionsterminate in inner annular horizontal flanges.

1. A damper of vibrations between two elements, comprising a center rodadapted to be rendered integral with one of said elements, a mountsurrounding the rod and adapted to be rendered integral with the otherelement, two elastically yieldable bellshaped membranes interconnectingsaid rod and said mount, each membrane having an apex at which meansdefine an aperture in which said rod is engaged and a peripheryconnected to the mount.
 2. A damper as claimed in claim 1, wherein saidrod comprises at its ends flanges adapted to retain said apices of saidmembranes externally.
 3. A damper as claimed in claim 2, wherein saidapices of said membranes are fixed to said flanges by adhesion.
 4. Adamper as claimed in claim 2, wherein said apices of said membranes arefixed to said flanges by vulcanization.
 5. A damper as claimed in claim1, wherein said rod comprises two parts screwed one into the other so asto make it possible to apply a prestressing to said membranes.
 6. Adamper as claimed in claim 1, wherein said rod further comprisesshoulders adapted to connect said apices of said membranes to said rodso that said membranes move with said rod.
 7. A damper as claimed inclaim 1, wherein said mount comprises two annular recesses in which saidperipheries of said membranes are held in position.
 8. A damper asclaimed in claim 7, wherein the mount comprises a center plate having anaperture through which said rod extends, two side walls in clampedrelation to said plate and having curved inner portions, said annularrecesses being defined by opposed faces of said plate and said curvedportions of said side walls.
 9. A damper as claimed in claim 8, whereinsaid membranes bear on said opposed faces of said plate and on saidcurved portions of said side walls.
 10. A damper as claimed in claim 7,wherein said mount is in a single piece.
 11. A damper as claimed inclaim 7, wherein said curved portions terminate in inner annularhorizontal flanges.